Method of manufacturing lightpolarizing bodies



Ch Hoom June 23, 1942. 2,287,598

METHOD OF MANUFACTURING LIGHT-POLARIZING BODIES c. H. BROWN Original Filed Dec. 28, 1937 70 INVENTOR new. 3M BY ATTORNEY 588,0PT1CSi uNlTEo STATES PATENT OFFICE METHOD OF MANUFACTURING LIGHT- POLARIZING BODIES Charles H. Brown, Baldwin, N. Y., assignor to Polaroid Corporation, Dover, Del., a corporation of Delaware Original application December 28, 1937, Serial No. 182,039. Divided and this application July 31, 1940, Serial No. 348,864

'sclaims. (CI. 88-65) This invention is a division of my co-pending be apparent that the wires and the areas beapplication Serial No. 182,039, filed December 28, tween them are all less in diameter than the 1937, and relates generally to methods of manu wavelengths of visible light. Under such circumfacturing light-polarizing bodies. stances, each wire will have a diameter not ex- Briefly stated, the light-polarizing body of the 5 ceeding .2 micron. Such a condition is preferred. present invention comprises an optical element It will be understood, moreover, that the length having embedded therein a plurality of parallelly f a h w s preferably y u r at r arranged electrically ond ggig wires, Vari than its width. The wires should be substanfeatures of the invention relate to the methods of tielly nger than the wavelengths of visi e l t. manufacturing this wire-embedded light-polar- The character f pol ri n f li h r n izing body, ted by structures embodying the invention may A better understanding of the invention may be controlled. For example, it has been previbe had by referring to the following description Ously Observed that light Which had Passed which is accompanied by a drawing, wherein: through a narrow slit less than .1 micron in Figure 1 shows the light-polarizing body made width was polarized perpendicular to the direcin accordance with the principles of the invention of the slit, w ere 0n in the slit to tion. It should be understood that although the .5 micron, the direction of polarization turned wires of this polarizing body are of such small through a r t anglediameter as to be substantially invisible, they One method of manufacturing such a polarizhave been greatly magnified and spaced apart ing body having embedded electrical conductors in the drawing for the purpose of illustration; is illustrated in 2 and includes arranging a Figs. 2 and 3 illustrate very generally, and by plurality of q y p thin, metallic Wires way of example only, the apparatus which may 3 in parallel on a suitable frame 4, packing powbe used in two dilierent methods of manufacturdered glass 5 a v nd' w the W r s, and ing the polarizing body of Fig. 1; and heating the whole mass in any suitable furnace Fig. 2a is a fragmentary sectional view through (if desired, a high frequency furnace), o that he wires and powdered glass of Fig. 2. theglass and wires are heated simultaneously, Fig. 1 shows my new polarizing body consisting the glass melting around the wires, then stretchpreferably of a glass plate I of any desired form s both the glass and Wires While e glass s having embedded therein extremely fine, parin a plastic state. This stretching will e1on ate allelly arranged electrical conductors 2, such as the glass and the wires and simultaneously bri fine platinum, although other electrical conductt e W s o er to t y Cutting e e oning materials, such as copper and silver, can also gated glass into sections nd rep in h h be used. These conductors should be extremely s and stretching p s r s times, the small in cross-section and arranged about 40,000 wires will be made extremely thin and be bro or more to the inch, in a direction perpendicular closer d o er together to give the d s ed to the direction of extension of the wires, in er per h During this Process 0f manuorder to provide extremely narrow transparent facture, the glass sections can be joined at their areas of substantially equal width between adjaide e s to pr v a w r i n whi h, n cent conducting elements. We thus have, in turn, may. after further stretching, be again efiect, a grating which exerts a, polarizing acjoined at its side edges to other similar sections. tion on light. The direction of polarization may Where it s desired to p y a polar ng body be parallel to the wires,'or at an angle thereto, of such e bed ed Conducting wires for Op depending upon the width of the apertures berr n purp the glass o y wi h ts emtween adjacent wires and the wavelength of the bedded W s can either be shaped W ile heated transmitted light. It is preferred that there be fi st 0 the s e general orm and then at least 80,000 of such wires per inch of lens, round o iv h ir d rv r else the measured in a direction at right angles to the g d 0f t ves can be made from a planar wires, although it will be appreciated that the polarizing blan provided the bedded wires number of wires can differ materially from those do no o e from the surfaces of t e ass. mentioned above without departing from the is Preferred, though not essential, that he spirit and scope of the invention. Where there temperature coefiicient of expansion of the wires are 80,000 minute wires per inch, and where the be not greatly different from that of the surtransparent areas between adjacent wires are rounding glass.

equal in diameter to the individual wires, it will Another and a preferred method of manufac turing my new light-polarizing body is shown in Fig. 3. The fine wire (preferably platinum) is first passed through glass tubing 8 having a relatively low melting point, and the glass tubing 8 and enclosed wire closely wound over a hollow drum 1, as shown. Drum 1 may be made of some ceramic material. The drum may be slowly revolved by means of a suitable low speed motor 9 whose shaft I is linked through reduction gears II to a pinion I2, in turn engaging a ring gear 13 attached to one end of the drum 1. Drum 'l is heated in any suitable manner, such as by a flame, not shown, in the interior thereof so that the adjacent turns of glass tubing 8 and embedded wires fuse into an integral mass. It is preferred that the drum 1 be relatively large, so that the glass tubing has a comparatively small radius of curvature as it is wound around the drum. If the type of glass tubing employed is such that it does not bend very readily, then either the glass tubing or the drum should be pre-heated to a temperature sufiicient to enable bending of the tubing around the drum. If the drum 1 is pro-heated, then the temperature thereof should be raised for fusing the glass and wires into an integral mass after the tubing is wound around the drum.

After the closely wound turns of glass tubing 8 and their wires are fused into an integral mass, the drum is permitted to cool somewhat, and the resulting glass and wire mass is out along a line AA parallel to the axis of the drum, after which the glass and Wires are stretched While the glass is still in a plastic state. Since the wires are substantially parallel, the stretching operation will elongate the glass and the wires, simultaneously bringing the wires closer together and forming a relatively thin ribbon. This resulting ribbon of glass with embedded parallelly arranged wires is, in turn, wound on the drum in the same manner as the glass tubing was previously wound on the drum, and the process of fusing, cutting and stretching repeated as above. This process can be repeated as often as desired in order to obtain a polarizer of a desired size having a required number of Wires per inch. It is a relatively simple matter to obtain a polarizer by this particular method of manufacture, which has 40,000 or more wires, each having a diameter less than .5 micron, arranged parallel to one another and embedded in the glass.

An advantage of using a polarizing body having embedded wires is that the body itself forms the lens without any need for sandwiching the same between glass blanks, as heretofore required when a film is employed.

Although glass has been mentioned as the preferred transparent optical element for the lightpolarizing body, it should be understood that my polarizing body is not limited to the use of glass, since other transparent optical materials made from plastics, in contradistinction to glass, may be employed in connection with embedded parallel wires to form my polarizing body.

Moreover, the methods of manufacturing my light-polarizing body are not limited to the precise steps outlined above, since various departures may be made in the processes without departing from the spirit and scope of the invention. For example, instead of passing the fine wire through a glass tubing, the glass tubing can be formed around the wire during the final process of making the fine wire.

It should be further understood that the lightpolarizing body of this invention may be used wherever there is need for such a body. For example, my new polarizing body may be used in spectacles, as a window, in headlights, in vehicular Windshields, in microscopes, as an analyzer in strain detection systems, etc.

Throughout the specification and claims, the expression "stretch will be deemed to include any elongation of the material to effect an alteration in the positioning of, or in the diameter of the embedded wires, or a contraction of the material to efiect the same purpose, or a combination of the two actions.

It should also be understood that the following claims are intended to cover all the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The method of manufacturing a polarizing body consisting of a transparent optical element having embedded therein a plurality of minute parallelly arranged electrical conductors, which comprises introducing parallelly arranged wires into said optical element, heating said wires and optical element simultaneously to bring said element into a plastic condition, and stretching said element and wires to elongate said wires and bring same closer together until the diameter of each wire has been reduced to substantially onehalf micron or less and until the distances between the traces of adjacent wires on a plane parallel to the surface of said element are reduced to substantially one-half micron.

2. The method of manufacturing a polarizing body consisting of a transparent optical element having embedded therein a plurality of fine parallelly arranged electrical conductors, which comprises introducing parallelly arranged wires into said optical element, said wires lying substantially 5 within a common plane, heating said wires andf optical element to a suitable temperature, stretching said element and wires to elongate said wires and bring same closer together, cutting said stretched element and wires into sections, joining said sections together, and repeating said process until the diameter of each wire has been reduced at least to one-half micron and the width of the aperture between adjacent wires 1 reduced at least to one-half micron.

3. The method of manufacturing a polarizing body consisting of a glass optical element having embedded therein a plurality of fine parallelly arranged electrical conductors, which comprises winding a continuous length of glass tubing having a fine wire contained therein over a portion of the length of a drum, heating said drum to fuse said glass into an integral mass, cutting said integral mass to form an extensible blank and stretching same while in a plastic state until the diameter of the wires and the width of the aperture between adjacent wires have been reduced substantially to one-half micron.

4. The process of manufacturing a polarizing body, which comprises forming a suspension of wiresin a stretchable, plastic, suspending medium paced from each other by distances substantially equal to the diameters of the wires and lying substantially within a common plane, and stretching said medium and wires simultaneously until the diameters of the wires and said distances are less than one-half micron.

5. The method of manufacturing a polarizing body consisting of a glass optical element having at. urns I A? fatent No- 2,287,598"

embedded therein a plurality of fine parallelly arranged electrical conductors, which comprises winding 8. continuous length of glass tubing having a fine wire contained therein over a portion of the length of a drum, heating said drum to fuse said glass and wires into an integral mass. cutting said integral mass to form an extensible blank and stretching same while in a plastic state until the diameter of the wires and the distances therebetween have been reduced substantially to one-half micron, the coemcient of expansion of said wire being substantially the same as that of said glass.

6. The process of forming a polarizing device, which comprises embedding a plurality of metallic wires of diameters not exceeding one micron, in substantially uniformly spaced, parallel relation in a substantially common plane within a sheet-like body of transparent, plastic material, the coefllcient of expansion of said wire being substantially the same as that of said plastic, rendering said body plastic, and stretching said body until the distance between adjacent wires in said plurality is less than the wave length of CERTIFICATE 'OF CORRECTION I search liocm visible light and until the diameters of said wires have been reduced at least by one-half.

7. The process of forming a polarizing device, which comprises embedding in a substantially common plane within a sheet-like body of transparent, stretchable material a plurality of metallic wire spaced apart from each other in substantially parallel relation by a distance approximately equal to the diameter of said wire, and stretching said body until said distance and the diameter of said wires is less than the wave length of visible light.

8. The process of forming a polarizing device, which comprises forming a suspension of wirelike metallic conducting elements in a suspending medium, said elements lying substantially within a common plane and being spaced from each other by distances substantially equal to the diameters thereof, rendering said medium plastic, and stretching said medium and elements simultaneously until the diameters of the elements and said distances are less than the wave length of visible light.

CHARLES H. BROWN.

June 25 19li2.

CHARLES H. BROWN.

.11: is hereby certified that error. appears in: the printed specification .of the above numbered. patent requiring correction as follows: Page 2,, sec- 0nd column, line 59, after "glass" insert thewords --e.nd wires-- and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. I Signed and sealed this pn day'of April, A. D. 1915. w

(Seal) Henry Van Ars dale A'cting Commissioner of' Patents CERTIFICATE OF cozmcnon. ment No. 2,237,598. June 25, 19!;2.

CHARLES H. BROWN.

It is hereby certified that error. appears in the printed gpecification of the above mnnbered' patent requiring correction as follows: Page 2, secand column, line 59, after 'glass' insert the words -and wires-- and that the bald Letters Patent should be read with this coxfrection therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 61m dny'or April, A. D. 19%.

v fienry van Aredale,

(Seal) Acting Commissioner of Patents. 

